Improvement in lever - escapements for watches



W. G. SUHDOF.

Lever-Escapements for Watches;

N0.155,044. I, Patented Sept.15,18 74 WITNESSES: v a]? v YHE GRAPRIC CIIPHD'YO'LITHJSx +1 PARK PLACER UNITED STATES PATENT QFFICE.

WILLIAM G. SOHOOF, OF OLERKENWELL, GREAT BRITAIN.

IMPRQVEMENT IN LEVER-ESCAPEMENTS FOR WATCHES.

Specification forming part of Letters Patent No. 1 55,044, dated September 15, 1874 application d May 23, 1874.

I To all whom it may concern other time-pieces, by which the separation of the unlocking action from the impulse action may be very nearly approached, the banking error obviated, and the injury to the balance and ruby pin of the roller, occurring in ordinary lever-watches through excessive 'vibratration of the balance by violent external motion, be prevented. Greater security is thereby given to the safety action, a double roller rendered unnecessary, and a stronger impulse imparted to the balance.

My invention consists in the planting-in place of the common notch of the roller, and a single pin or jewel in the lever acting on each side of the notch alternately of a jewel or other pallet inthe middle of a small crescent-shaped recess at the edge of the roller, which jewel engages two upright pins or pallets of the lever, and performs the unlocking action in connection with or without a rubypin near the center of the roller. The resilient or elastic banking of the lever is obtained in connection with banking-pins of a pivoted lever plate or piece, and a yielding spring action thereon, which gives way when banking occurs. The resilient action may also be produced by mounting the spring upon the lever as a substitute for the spring-plate, and using stationary banking-pins at both sides of the lever. B

In the accompanying drawing, Figure 1 represents a front view of my improved lever-escapement for watches and other time-pieces; Fig. 2, a side view of the same. Figs. 3 and 4, respectively, are front and side views of modifications of the lever-escapement; and Fig. 5 is a modification of the lever in its simplest form.

Similar letters of reference indicate corresponding parts.

A represents the lever, which turns on a fulcrum, a, at suitable distance from the roller B and banking-pins Cl. The roller B has a jewel or other pallet, I), placed in the middle of a crescent-shaped recess, 1), cut into the edge of the same. Palletb engages the two upright pins or pallets cl placed on the upper swinging end of lever The escapement-wheel D is, preferably, made of steel. with gold teeth for lessening the weight and friction on the pawl E, and with ten teeth instead of fifteen, so as to reduce the swinging distance of the pawl, and obviate almost entirely thev necessity of oiling the staff of the same. The wheel D is placed between the pawl E and the balance-staff, whereby the pressure of the staff is lessened as the force is transmitted on the same side on which it is given. The yielding banking-piece G, is mounted freely on the fulcrum of lever A, and kept in position by the controlling-spring H. The banking-pins G are fixed to the swinging end of the banking-piece, and are acted upon by the lever A. The unlocking-pin f is placed as near as possible to the center of the roller B, or on a separate roller, or as a ruby-arm on the balance-staff itself. It acts on the projecting prongs of lever A, and produces an almost complete separation of the unlocking and impulse action. The vibration of the balance is also enlarged, because the unlocking takes place under more favorable leverage and diminished friction as compared with the common lever and roller actions.

The resilient action is as follows: The unlocking-pin f, after having traversed a full turn from the position of rest without having finished its motion, will strike against the back of one of the prongs of the lever A, which, resting against one of the bankingpins e, will throw the banking-piece Grback so far as to allow the unlockingpin to pass the prong, thereby preventing the rebounding of the balance, which is called the banking error, and also preventing injury to the balancepivots.

' For the purpose of simplifying this con struction, the resilient spring H may be placed directly onthe" lever A, being either made of one or two pieces, and applied to a stud at the lower end thereof, extending, with the legs, edgewise along lever A, andbeing held in position within and by the prongs of the same, so as to form, by projecting beyond the same, the unlocking surfaces, dispensing with a separatepivoted banking-piece. The action is similar to the one just described, only that here the spring ends are acted upon directly by the unlocking-pin and the ordinary rigid banking-pin 'used, as shown in Figs. 4 and 5.

The simplest form of escapement is shown in Fig. 5, in which the pin or pallet 1) acts both as unlocking-pin and as receiver of the impulse, so 'that the prongs of the lever may be done away with. The two pins (1, in this as well as in the other cases, embrace the impulse-pin b long enough to bring the opposite crescent corner of the roller in position to prevent the return of the lever by engaging with the other of the two pins.

I do not limit myself to the use of any particular material for pallets pins, levers, or roller, nor do I confine myself to precise arrangements.

Having thus described my invention, I claim as new and desire to secure by Letters Patent- The lever A, having impulse-pins d, in combination with the roller B, having recess 1) and pin 1), and a yielding elastic bankingpiece, substantially in the manner and for the purpose set forth.

The above specification of my invention signed by me this 31st day of March, 1874.

WILLIAM GEORGE SOHOOF.

Witnesses:

FREDERICK JAMES BRITTEN, RICHARD STRACHAN. 

